What Effect Can Food Have While Taking Medication?

As a pharmacist, I frequently come across situations that show why it's so important for patients to tell their doctors, pharmacists, and other healthcare providers about all of the prescription and over-the-counter (OTC) medications, vitamins, nutritional supplements, and herbal products they are taking. We even need to know what a patient has eaten recently because it can affect how a prescription medication works.

For example, if you are receiving warfarin (Coumadin) therapy to help reduce blood clots, you may not know that certain foods or supplements can make your blood “too thin.” This can cause bruising and bleeding.

I have seen patients who are admitted to the hospital with this problem. After we spend some time talking to the patient, we often find out that they have been drinking green tea or using supplements like glucosamine—both of which can make blood thinner.

On the flip-side, I have also seen warfarin therapy patients admitted to the hospital with a blood clot in their leg. This can happen if the patient has been eating more leafy greens than usual, such as spinach, romaine lettuce, broccoli, etc. These foods are all high in vitamin K, which can decrease the effect of warfarin.

These stories show how important it is for you to tell your healthcare providers about every prescription and OTC medication, herbal supplement, and vitamin you are taking as well as information about the foods you have eaten recently.

Why should I keep a list of my medications?

By keeping a list of your medications and bringing it with you to each doctor's appointment or trip to a pharmacy, you can provide important information to your doctor and pharmacist to improve your health and prevent potential problems.